Hydraulic turbine governor



May 12, 1942.

HYDRAULIC TURBINE GOVERNOR Filed March 3-, 1941 CL USING w. J. RHEINGANS2,283,127

l atenteci May 12, 1942 l UNITED STATES PATENT OFFICE HYDRAULIC TURBINEGOVERNOR William J. Rheingans, Wauwatosa, Wis., assignor toAllis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation ofDelaware Application March 3, 1941, Serial No. 381,528

12 Claims. (Cl. 253-143) This invention relates generally to prime movercontrol systems and particularly to systems con-' trolling a prime moverof the type having adjustable runner vanes.

When the prime mover governed is a hydraulic turbine with adjustablerunner vanes, it is necessary to adjust the vanes to a steep angle forproducing the maximum torque during starting, and it is necessary tomake such adjustment automatically. The control system should thereforeprovide for setting the runner vanes to a steep angle prior to startingand such setting should be relinquished to the normal vane controlmechanism at least as soon as the machine is at its normal operatingspeed. It is also desirable that means be provided by which thesteepness of the runner vane setting may be adjusted, by which the speedat which the runner vane setting will change and by which the time atwhich the runner vanes will be returned to L the normal vane operatingmechanism relative er having adjustable runner vanes in which the runnervanes are caused to assume a steep angular position prior to starting ofthe prime mover to increase the starting torque thereof and are returnedto normal position after the starting operation is completed.

Another object of the invention is to provide a control system for aprime mover having adjustable runner vanes in which system the steepnessof setting of the runner vanes prior to starting 4 of the prime mover isadjustable.

Another object of the invention is to provide a control system for aprime mover having adjustable runner vanes in which system the runnervanes are set to a steep position prior to starting of the prime moverand in which the speed at which the runner vane setting is changed tothe normal position can be readily varied.

Another object of the invention is to provide a control system for aprime mover having adjustable runner vanes in which system the runnervanes are set to the steep position prior to starting of the prime moverand in which the moment at which the setting of the runner vanes takesplace relative to the setting of the gate vanes may be adjusted.

Objects and advantages other than those above set forth will be apparentfrom the following description when read in connection with theaccompanying drawing which diagrammatically illustrates a hydraulicturbine of the adjustable runner vane type having applied thereto anautomatic speed control system embodying the means for controlling thesteepness of setting, the time for changing the setting, and the rate ofchange in the setting of the adjustable runner vanes accordingto thepresent invention.

The various elements comprising the control system are not shown intheir relative positions, their truesizes, nor in their relativeproportions, but are shown diagrammatically to more clearly facilitateexplanation of the construction and operation of the system.

Referring more particularly to the drawing by characters of reference,the control system is shown as applied to a prime mover such as ahydraulic turbine generally I designated at [0 and shown as being of theadjustable propeller type driving an alternating current generator I lconnectable with and disconnectable from the usual power line byconventional switch gear means well known in the art and therefore notshown. The turbine [0 comprises the casing [2 which forms a peripheralwaterfinlet in which are mounted a series of movable vanes l3 forming agate. The term gate is intended to include means other than those"disclosed and which may be used for the purpose of controlling andguiding the flow of fluid pressure to any prime mover to which thegoverning system of the present invention is applied. The gate vanes aremounted on stems l4 journaled at the top and bottom in portions of thecasing I2. The upper stem portions-extend through the upper portion ofthe casing to provide for attachment of aconventional linkage connectionwith a shifting ring [6 which is-adapted to be shifted into differentpositions and to control the positions of the gate vanes and hence tocontrol the flow of fluid to the turbine. The shifting of ring i6 isconnected with and actuated by the piston ll movable within a cylinder.I8,It he piston and cylinder forming a fluid-pressure operatedservomotor.

The turbine I0 is connected with the generator I l by a hollow shaft I9which is supported against movement relative toits axis by a bearing 2|and on which is mounted the turbine runner comprising a hub 22 fromwhich extend, substantially radially, a series of vanes 23, journaled insuitable bearings in the hub. The inner ends of the vanes 23. areseverally provided with trunnions 26 and are connected by linkages 21with a cross head 28 which is guided tov be reciprocated axially of theshaft H) by an operating rod 29. It will be understood that thepositions of the runner vanes relative to each other govern the area ofthe fluid flow passages for openings between the vanes and thatadjustment of the runner vanes increases or decreases the area of theflow passages depending upon the direction of the movement of the vanes.The operating rod 29 extends upwardly through the runner shaft l9 and isfixed to a piston 3| movable within a cylinder 32, the piston andcylinder forming a fluid pressure operated servomotor which is mountedin or is formed as a portion of the runner shaft, preferably adjacentthe point where the hollow runner shaft is joined to the hollowgenerator shaft 33. A tube 34 extends through the hollow generator shaftfor the purpose of supplying fluid pressure to the servomotor chamberbelow the piston 3|. A passage 36 about the tube 34, connects with thelower chamber of a distributing head 31 secured to the top of thegenerator frame and supplies fluid for the downward movement of thepiston 3|. The tube 34 is fixed to and rotates with the shaft l9 andsupplies fluid pressure for the upward movement of the piston 3| by wayof an inclined passage 38 through the piston 3| and is provided withperforations 39 in the portion of the tube extending into the upperchamber of the distributing head 31.

Pressure to the runner vane servomotor 3|, 32 is controlled by a pilotvalve 4| which is governed by a pilot valve operating mechanismincluding an extension 42 from the piston H of the gate operatingservomotor I1, I8, connected with an arm 43 fixedly mounted on arotating shaft 44 and with one arm of a bell crank 45 separatelymounted. The shaft 44 has fixedly mounted thereon an arm 46 connectedwith a rod ,41, the other end of which is connected with a cam 48. Thecam 48 is in the form of a bell crank mounted on a fixed pivot point49and engages a roller mounted on a lever 52 which is pivotally mounted ata fixed point 63 and is biased downwardly at one end by a spring 54connecting the end of the lever with a fixed point in the controlsystem. The lever 52 is connected by a link 56 with one end of afloating lever 51 to which is connected the stem of the pilot valve 4|.Movement of the gate'servomotor piston |1 transmits motion throughleverage 43, 46 and 41 to the cam 48 from which the motion istransmitted through a second leverage including roller 5|,lever 52, link56 and lever 51 by which the pilot valve 4| is moved to admit fluidpressure from a pipe 58 through pipes 59 or 6| into the pressure head31. Fluid from the pressure head 31 is also discharged through the pipes59 or 6| to a discharge pipe 62. The cam 48 provides means for producinga topographic surface by which a different relation may be obtainedbetween the setting of the gate l3 and the positioning of the runnervanes 23. The cam is preferably made of laminated material to facilitateformation of the proper topographic surface thereof after tests havebeen made with the entire unit in operation in its final setting.

When the gate opening is small and the runner vanes are in acomparatively flat position, the starting torque of an adjustablepropeller type turbine is very low. A relatively long period of time istherefore required to bring the turbine up to the speed at which theunit may be connected to the transmission line. Further, with the runnervanes'in'a relatively flat position, the gate must be opened arelatively large amount to overcome the starting friction of the primemover unit. It is then necessary to move the gate quickly in a closingdirection to prevent over-speeding of the turbine after rotation hasbegun. Means are therefore provided herein by which the runner vanes mayautomatically be initially set in a comparatively steep position andthen returned to the desired operating angle and particularly in whichthe degree of such steep positioning, the speed at which the vanesreturn to the normal operating angle and the moment, relative to thesetting of the gate vanes, at which the runner vanes are returned to thenormal operating angle, may be adjusted. The one arm of the cam bellcrank 48 is connected at the end thereof with a frame 1| to receive thethreaded end of a valve stem 12. The threaded portion of the valve stem12 is provided with nuts 13 and 14 within and adjacent the ends of theframe 1|. The frame 1| cooperating with the nuts 13 and 14 on the valvestem 12 provides a lost motion connection between the cam bell crank 43and a valve 16. The valve 16 is connected with a source of fluid underpressure by way of a pipe 11 and controls the supply of fluid pressurethrough a pipe 18 and a needle valve 19 to the cylinder 8| of aservomotor having the piston 82 connected with the end of the lever 52extend ing. beyond the fixed pivoting point 53 thereof. An adjustablestop 83 extends upwardly through the end of the servomotor cylinder 8|,for the purpose of controlling the degree of movement of the servomotorpiston 82 and hence the steepness to which the runner vanes may be set.Discharge of the fluid pressure from the servomotor 8|, 82 takes placeby way of needle valve 19, pipe 18 and valve 16 and a discharge pipe 84.Adjustment of nuts 13, 14 controls the moment in the control systemcycle at which pressure is supplied to or may discharge from servomotor8|, 82'and hence controls the moment, relative to the gate setting, atwhich runner vanecontrol is returned to the normally operating portionsof the system. The speed at which the runner vane setting may be changedin either direction is determined by the adjustment of the needle valve19 which controls the rate of flow of pressure to and from theservomotor 8|, 82.

Means must also be provided by which the runner pilot valve 4| isrestored to the neutral or mid-position after each operation of thevalve in either direction. The restoring movement is derived from theinner shaft tube 34 by way of a rod 86 extending beyond the fluiddistributing head 31 and connecting with one arm of a bell crank 81pivotally mounted at 88. The other arm of the bell crank 81 is connectedby Way of a rod 89 with the floating lever 51 for the pilot valve 4|.

The interconnection of large power generating system in which momentaryload fluctuations are relatively small and occur over a relatively largeperiod of time, as compared with the total load, necessitates governingmeans of extreme sensitivity capable of instant response to theslightest speed variations to maintain adequate distribution stabilityand proper frequency regulation in the distribution system. Such meansare herein shown as comprising a unit including an electric motorconnected with and therefore responsive to the frequency (or speed)variations of the prime mover generating unit. The electric motor 9|drives a set of fiyballs 92 which controls a servomotor for impartingmotion to a floating lever 93 controlling the operation of a pilot valve96 which regulates the flow of. fluid pressure to the gate operatingservomotor I1, I 8. The structure of the motor operated socalled flyballhead herein only diagrammatically illustrated, is shown in detail in U.S. Patent 2,106,684, issued to J. J. Ring and B. R. Nichols and A. Pfau,on January 25, 1938, and will therefore not be further described. Fluidpressure is supplied to the pilot valve 96 through the pipe 58 and issupplied to the two sides of the servomotor piston I! by way of pipes.91 and 98. Fluid pressure is discharged from the servomotor through thevalve 96 by way of a pipe 99. Any change in the conditions of thedistribution line which results in a change of speed of the motor 9| isimmediately translated'into movement of the flyballs 92 which act on thefloating lever 93 to change the setting of the pilot valve 96. The gateoperating servomotor II, I8 therefore immediately commences to vary theopening of the gate I3 to change the flow of fluid to the prime mover l6dependent on the degree and the sense of the speed change. Floatinglever 93 is connected at one end with one end of a lever IIJI having itsother end connected with the stem of the valve body of the pilot valve96. The lever IIlI is fulcrumed on a nut I62 traveling on a screw I63which is fixedly mounted and is rotatable either by a hand wheel I04shown or by other suitable means known.

Movement of the gate servomotor II, I8, must, however, be interruptedbefore the eifect of-decreasing or increasing speed of the prime mover Iwould be apparent in the distribution system and hence would produce achange in the speed of the governor motor 9| to thereby prevent over orunder regulation or so-called hunting of the unit. Pilot valve 96 musttherefore be restored or returned to its neutral or mid-position with atime delay after the operation thereof. Such restoring or compensatingmeans includes the servomotor piston rod extension 42 and the bell crank45, to one arm of which is connected a rod I06 pivotally connected withthe cylinder of a dashpot I61, the structure of which is well known inthe art. The piston of the dashpot IOI is connected by a rod I68 withone end of the floating lever 93.

Theentire structure is shown in the position assumed by the variouselements thereof at standstill in which the gate is closed and therunner vanes are in the steep tilt position. To place the turbine inoperation, synchronizing screw I93 is rotated to raise the end of leverIIJI connected with pilot valve 96, the other end of the lever II'IIbeing retained in its position by its connection with the movablefloating lever 93. The valve body of the pilot valve 96 is raised topermit fluid under pressure to flow through the pipe 91 to the left-handside of the piston I! which moves to open the gate I3 and admit fluidunder pressure to act on the runner vanes 23. The runner vanes arealready in steep tilt position and the fluid acting thereon thereforeimmediately produces a high torque to start the prime mover generatingunit in rotation. Movement of the piston I1, however, rocks bell crank43 to pull down on rod I66 and the end of the floating lever 93 to raisethe end of lever IIJI connected with floating lever 93, thus returninglever IM to the horizontal position which returns the valve 96 totheneutral position shown in the drawing. The above sequence of operationsis therefore repeated until the prime mover generating unit is atitsfull' operating speed at which it may be connected with the transmissionline in parallel with-other prime mover generating units supplying theline (not shown). When close to'full operating speed, the. motor SH andthe flyballs 92 assume control of the pilot valve 96, as is well known.

Movement of the piston I'I mentioned above, also moves arm 46 in acounterclockwise direction to push upwardly on rod 41 which rocks thecam bell crank 48 to pull the frame II toward the right. The frame IImoves until the end thereof comes into contact with the nuts I3 andpulls the valve stem I2 of the valve I6 toward the right to shut ofi thepressure inlet 11 and to open the pipe I8 to the discharge or outlet 84.The spring 54 acting on lever 52 depresses the end of such lever andexerts a lifting'forceon the piston 82 which forces fluid out of thecylinder 8I through the needle valve I9 untilthe roller 5I is broughtinto contact with the surface of the cam 48. Downward movement of thelever 52 and'of the rod 56 depresses one end of the floating lever 51 tomove the valve body of the valve 4I into position to (supply pressure byway of the pipe 59 and the passage 36 to'the space above the piston 3I.The piston 3I then moves downwardly to turn the runner vanes into aflatter position.

Downward movement of the piston 3| pulls the end of the floating lever8! downwardly to raise the end of the floating lever 51 connectedtherewith which returns the pilot valve M to the midposition andinterrupts the flow of pressure to the servomotor 3 I, 32. The primemover generating unit and the control system therefor are now in thenormal operating. condition in which the fiyballs control the action ofthe gate servomotor II, I8, and the movement of th runner servomotor 3I,32 is controlled by the position of the cam 48 actuated in response tooperation of the gate servomotor II, I8 to maintain a definite relationbetween the gate opening and the runner vane position.

Shutdown of the unit requires reversal of the above operationsgenerally, and hence requires lowering of the end of lever IIII to shiftvalve 96 for admitting pressure to the right hand side of the piston IIto move gate I3 into the closed position. Movement of the piston IItoward the left rocks the lever arm 43 to pull down on the rod 41 whichrocks the cam bell crank 48 in clockwise direction. Such movement of thecam bell crank 48 pushes on frame II until the end of the frame comesinto contact with the nut I4 and thenmoves valve I6 to the positionshown atwhich pressure is admitted by way of the pipe I8 and the valveI9 ,to the upper side of the servomotor M, 82. The piston 82 then movesdownwardly until it meets the stop 83 and tilts the lever- 52 to theposition shown. Upward movement of the one end of" the lever 52 pullsupwardly on rod 56 to raise one end of the floating lever 51 and to movethe valve 4| to the position shown at which pressure is admitted by wayof the pipe 6|, the

9| and the flyball head 92 connected with the pilot valve 96 forcontrolling the servomotor I1,

l8 connected with the gate [3 together with the leverage 42, 45, I06 I01and I08 connected with one end of the floating lever 93 for restoringthe pilot valve 96 to the neutral or mid-position. The

means for adjusting the runner vanes 23 responsive to the action of thegate operatingmeans includes the arm; acting by way of the rod 41 on thecam bell crank 48 to raise and lower the end of the lever 52 and the rod56 connected with the floating lever 51 for actuating the valve 4| whichcontrols the flow of'pressure to the servomotor 3|, 32 by way of tube 39and the leverage 81, 88 and 89 for restoring the valve 4| to themid-position. The servomotor BI, 82 controlled by the valve 16 providesmeans actuated by the gate operating means for causing a temporarystarting of the runner vanes 23 at a steep angle and the action of suchtemporary setting control means is modified by the frame H and the nuts13 and 14 on the valve stem 12 which form an adjustable lost motionconnection for controlling the moment in the cycle of operation of thegate operating means at which the steep setting control means becomeseffective and inefiective. Adjustment of the needle valve 19 providesmeans for adjusting the rate of fluid supply to the servomotor 8|, B2and therefore provides means for adjusting speed of movement of the vanesteep setting control means. The stop 83 limits the movement of theservomotor piston 82 in the steep setting direction and thus providesmeans for controlling the degree of movement of the steep settingcontrol means. I

Although but one embodiment of the present invention has beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims. 7

It is claimed and desired to secure by Letters Patent:

1. In a control system for a prime mover having a gate controlling theflow of fluid pressure thereto and having a runner with adjustablevanes, means for operating the gate responsive to the speed of the primemover, means for adjusting the runner vanes responsive to actuation ofsaid gate operating means, a fluid pressure operated servomotor forcausing the temporary setting of the runner vanes at a steep angle,avalve actuated by said gate operating means for controlling the flow ofpressure to said servomotor, and adjustable means actuated by said gateoperating means for controlling said valve to vary the moment in thecycle of said gate operating means of actuation of said servomotor.

2. In a control system for a prime mover having a gate controlling flowof fluid pressure thereto and having a runner with adjustable vanes,means for operating the' gate responsive to the speed of the primemover, means for adjusting the runner vanes responsive to actuation ofsaid gate operating means, a fluid pressure operated servomotor forcausing the temporary setting of the runner vanes at a steep angle, avalve actuated by said gate operating means for controlling the flow ofpressure to said servomotor, an adjustable lost motion connectionbetween said gate operating means and said valve and means for adjustingsaid lost motion connection to vary the moment in the cycle of said gateoperating means of actuation of said'servomotorr V 3. In a controlsystem for a prime mover having a gate controlling the flow of fluidpressure thereto and having a runner with adjustable vanes, means foroperating the gate responsive to the speed of the prime mover, means foradjusting the runner vanes responsive to actuation of said gateoperating means, means actuated by said gate operating means for causingthe temporaryrsetting of the runner vanes at a steep angle, and meansfor adjusting the speed of movement of said vane steep setting means.

4. In a control system for a prime mover having a gate controlling theflow of fluid pressure thereto and having a runner with adjustablevanes, means for operating the gate responsive to the speed of the primemover, means for adjusting the runner vanes responsive to actuation ofsaid gate operating means, a servomotor actuated by said gate operatingmeans for causing the temporary setting of the runner vanes at a steepangle, and means for adjusting the speed of movement of said servomotor.

5. In a control system for a prime mover having a gate controlling theflow of fluid pressure thereto and having a runner with adjustablevanes, means for operating the gate responsive to the speed of the primemover, means for advanes, means for operating the gate responsive to thespeed of the prime mover, means for adjusting the runner vanesresponsive to actuation of said gate operating means, means actuated bysaid gate operating means for causing the temporary setting of therunner vanes at a steep angle, and means for controlling the degree ofmovement of said vane steep setting causing means. i

7. In a control system for a prime mover having a gate controlling theflow of fluid pressure thereto and having a runner with adjustablevanes, means for operating the gate responsive to the speed of the primemover, means for adjusting the runner vanes responsive to actuation ofsaid gate operating means, a servomotor actuated by said gate operatingmeans for causing the temporary setting of the runner vanes at a steepangle, and means for controlling the degree of movement of saidservomotor to limit the steepness of setting of the runner vanes.

8. In a control system for a prime mover having a gate controlling theflow of fluid pressure thereto and having a runner with adjustablevanes, means for operating the gate responsive to the speed of the primemover, means for adjusting the runner vanes responsive to actuation ofsaid gate operating means, means actuated by said gate operating meansfor causing the temporary settingof the runner vanes at a steep angle,anda stop for controlling the degree of movement of said vane steepsetting causing means to limit the steepness of setting of the runnervanes.

9. In a control system for a prime mover hav- I ing a gate controllingthe flow of fluid pressure thereto and having a runner with adjustablevanes, means 'foro'perating the gate responsive to the speed of theprime mover, means for adjusting the runner vanes responsive toactuation of said gate operating means, a servomotor actuated by saidgate operating means for causing the temporary setting of the runnervanes at a steep angle, and a stop for controlling the degree ofmovement of said servomotor to limit the steepness of setting of therunner vanes.

10. In a control system for a prime mover having a gate controlling theflow of fluid pressure thereto and having a runner with adjustablevanes, means for operating the gate responsive to the speed of the primemover, means for adjusting the runner vanes responsive to actuation ofsaid gate operating means, a fluid presmotor for controlling the speedof movement means for controlling the flow of pressure togree ofmovement of said servomotor to limit the steepness of setting of therunner vanes.

12. In a control system for a prime mover having a gate controlling theflow of fluid pressure thereto and having a runner with adjustablevanes, means foroperating the gate responsive to the speed of the primemover, means for adjusting the runner vanes responsive to actuation ofsaid gate operating means, a fluid pressure operated servomotor forcausing the temporary setting of the runner vanes at a steep angle, avalve actuated by said gate operating means for controlling the flow ofpressure to said servomotor, an adjustable 10st motion connectionbetween said gate operating means and said valve, means for adjustingsaid lost motion connection to vary the moment in the cycle of said gateoperating means of actuation of said servomotor, a stop for controllingthe degree of movement of said servomotor to limit the steepness ofsetting of the runner vanes, and a valve arranged between saidservomotor and the first said valve to adjust the rate of flow ofpressure to said servomotor for controlling the speed of movementthereof.

WILLIAM J. RHEINGANS.

